Dielectric Strength Testing - GE 239 Instruction Manual

2 INSTALLATION
j) GROUNDING
• SAFETY GROUND (13): Connect the safety ground terminal 13 to a reliable system ground
within the starter using heavy gauge wire. For safety, all metal parts within the 239 are connected
to this ground terminal. Shield terminals 20/48 and RTD COM terminals 51/54/57 are internally
connected to the safety ground, terminal 13.
• FILTER GROUND (14): Using #12 gauge wire or ground braid, connect this terminal to a solid
system ground, typically a copper bus in the starter. Extensive filtering and transient protection is
built into the 239 to ensure reliable operation under harsh industrial operating environments.
Transient energy must be conducted back to the source through filter ground terminal 14. The fil-
ter ground terminal is separated from the safety ground terminal to allow dielectric testing of a
starter with a 239 wired up.
When properly installed, the 239 will meet the interference immunity requirements of IEC 801 and
ANSI C37.90.
It may be required to test a complete motor starter for dielectric strength with the 239 installed. This
is also known as "flash" or "hipot" testing. The 239 is rated for 1530 V AC isolation for 1 minute (or
1836 V AC for 1 second) between relay contacts, CT inputs, control power inputs and safety ground
terminal 13. Some precautions are necessary to prevent damage to the 239 during these tests.
Filter networks and transient protection clamps are used between the control power, serial port,
switch inputs, analog output, thermistor, RTDs inputs and the filter ground terminal 14 to filter out
high voltage transients, radio frequency interference (RFI) and electromagnetic interference (EMI).
The filter capacitors and transient absorbers could be damaged by the continuous high voltages rel-
ative to ground that are applied during dielectric strength testing. Disconnect the filter ground termi-
nal 14 during testing of the control power inputs. Relay contact and CT terminals do not require any
special precautions. Do not dielectric strength test the serial port, thermistor, RTD or analog
output terminals else the 239 internal circuitry will be damaged.
GE Multilin
Courtesy of NationalSwitchgear.com
239 Motor Protection Relay
2 INSTALLATION

2.4 DIELECTRIC STRENGTH TESTING

2
2-13